1. Field of the Invention
The invention relates to an adjustable mattress support arrangement for adjustably supporting a matress in the cab of a vehicle such as a truck. More specifically, the invention relates to such an arrangement which utilizes expandable air cushions for the adjusting process, the expandable air cushions being supported by mechanical means at the front and rear end of each expandable air cushion.
2. Description of Prior Art
It is known in the prior art to provide suspension systems or adjustment systems for mattresses on beds in the cabs of trucks. Such systems are illustrated in, for example, U.S. Pat. No. 3,371,359, Dome, Mar. 5, 1968, U.S. Pat. No. 3,760,436, Zach et al, Sep. 25, 1973, U.S. Pat. No. 4,144,601, Anderson et al, Mar. 20, 1979, U.S. Pat. No. 4,196,483, Lafler et al, Apr. 8, 1980 and U.S. Pat. No. 4,669,139, Richter, Jr., Jun. 2, 1987.
The '359 patent teaches a mattress suspension system which includes suspension units 40 and 41 at either end of the system and shock absorbers 120 and 121, also at either end of the system. The mattress is vertically adjustable by action of the suspension system.
The '436 patent includes fore and aft isolation mechanisms for isolating the mattress from pitching movements in the cab of a truck. The isolation mechanism consists of parallel links at either end of the mattress suspension system which forms a pendulum-like arrangement. Vertical suspension is provided by a scissors linkage and a gas spring.
In the '601 patent, cushioned movement for a mattress in the cab of a truck is provided, in the vertical direction, by scissored linkages, at each end of the mattress, together with air cushions. The ends of one of the links of each scissor include a roller, mounted in a guide, to provide cushioning in the horizontal direction.
An adjustable mattress support for use in the cab of a truck, as taught in the '483 patent, includes a raising means consisting of intersecting linkage arrangements at both ends of the support together with a fluid cylinder. The raising means can be operated to raise or lower the mattress vertically.
The '139 patent teaches a multipositional sleeper for the cab of a truck which consists of an upper body unit, for supporting the upper body either horizontally or at an acute angle to the horizontal and a lower body unit which supports the legs either horizontally or in a knee bent position. Both upper and lower body units are controlled by air springs.
Also known in the art is a vibration damping support, for example, a suspension unit for a stretcher as taught in U.S. Pat. No. 4,541,134, Black et al, Sep. 17, 1985. It consists of a pair of cantilever arms controlled by respective gas liquid suspension units.